XC2287 / XC2286 / XC2285
XC2000 Family Derivatives
Preliminary
Functional Description
Based on these hardware provisions, most of the XC228x’s instructions can be executed
in just one machine cycle which requires 15 ns at 66 MHz CPU clock. For example, shift
and rotate instructions are always processed during one machine cycle independent of
the number of bits to be shifted. Also multiplication and most MAC instructions execute
in one single cycle. All multiple-cycle instructions have been optimized so that they can
be executed very fast as well: for example, a 32-/16-bit division is started within 4 cycles,
while the remaining cycles are executed in the background. Another pipeline
optimization, the branch target prediction, allows eliminating the execution time of
branch instructions if the prediction was correct.
The CPU has a register context consisting of up to three register banks with 16 word
wide GPRs each at its disposal. One of these register banks is physically allocated within
the on-chip DPRAM area. A Context Pointer (CP) register determines the base address
of the active register bank to be accessed by the CPU at any time. The number of these
register bank copies is only restricted by the available internal RAM space. For easy
parameter passing, a register bank may overlap others.
A system stack of up to 32 Kwords is provided as a storage for temporary data. The
system stack can be allocated to any location within the address space (preferably in the
on-chip RAM area), and it is accessed by the CPU via the stack pointer (SP) register.
Two separate SFRs, STKOV and STKUN, are implicitly compared against the stack
pointer value upon each stack access for the detection of a stack overflow or underflow.
The high performance offered by the hardware implementation of the CPU can efficiently
be utilized by a programmer via the highly efficient XC228x instruction set which includes
the following instruction classes:
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Standard Arithmetic Instructions
DSP-Oriented Arithmetic Instructions
Logical Instructions
Boolean Bit Manipulation Instructions
Compare and Loop Control Instructions
Shift and Rotate Instructions
Prioritize Instruction
Data Movement Instructions
System Stack Instructions
Jump and Call Instructions
Return Instructions
System Control Instructions
Miscellaneous Instructions
The basic instruction length is either 2 or 4 bytes. Possible operand types are bits, bytes
and words. A variety of direct, indirect or immediate addressing modes are provided to
specify the required operands.
Data Sheet
40
V0.91, 2007-02
Draft Version
INFINEON [ Infineon ]
